Minor whitespace fix for clutter color parsing of hsla(h,s,l,a)

Previously, if there was whitespace between "l" and the comma before the
alpha value, parsing would fail.  This patch allows that whitespace
making it consistent with whitespace being allowed everywhere else.

https://bugzilla.gnome.org/show_bug.cgi?id=663594

clutter/clutter-color.c

@@ -589,6 +589,7 @@ parse_hsla (ClutterColor *color,
   str += 1;
 
   l = CLAMP (number / 100.0, 0.0, 1.0);
+  skip_whitespace (&str);
 
   /* alpha (optional); since the alpha channel value can only
    * be between 0 and 1 we don't use the parse_rgb_value()